I see, I figured out the link issue: it should be https://raysfiles.com/.. NOT http (i.e. secure vs. non-secure). It has been fixed now. Please try again.
Are you using static IP assignment on OpenSprinkler? If so, yes that will be erased so it goes back to DHCP mode. You can always click button B1 to find the IP address it’s assigned by the router. In fact, we always recommend not changing DHCP settings on OpenSprinkler, instead, use the router’s DHCP reservation to reserve a fixed IP, that’s a much better way to manage fixed IP.
After you upgrade the firmware, and find out the IP address, then you can still go to:
http://os_ip/su
to change the UI link to your local server. You should probably update the content on your local server too, as new firmwares generally have new features that require matching UI files. If you don’t upgrade the content on your local server, some of the new features won’t be visible.